PGI-1 Talk: Quynh Anh T Nguyễn

Quantum Theory of Materials Seminar *Two Invited Talks today*

Spintronics of W alloys: first-principles study

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W alloys have recently drawn attention due to their large spin Hall angle, which has practical promise in spintronics [1,2]. 
Driven by recent experimental study [3-5], we investigate spin Hall conductivities of W alloys using first-principles calculations. 
For all, we have calculated formation energy. Additionally, we performed the Berry curvature and the symmetry analysis to explain the SHC features. Without doping, pure β-W has SHC of -818 S/cm. For X = N, W2N exhibits SHC of -966 S/cm, significant increase over β-W, attributed to a large negative spin Berry curvature (Ω<0) from the anti-crossing point near the Fermi level (EF). For X = Si, W-Si alloys show even larger SHC of -1306 S/cm at 3.13% Si. For X = Ti, W-Ti alloys reach the largest SHC of -1461 S/cm at 12.5% Ti among W-X alloys, 78.61% increase over β-W. For W-Si and W-Ti alloys, band structure is engineered upon doping effect, including tuning EF and band degeneracy lifting, resulting in an enhancement of Ω<0 and SHC.


[1] K.-U. Demasius, T. Phung, W. Zhang, B. P. Hughes, S.-H. Yang, A. Kellock, W. Han, A. Pushp, and S. S. P. Parkin, Nat. Commun. 7, 10644 (2016). 
[2] X. Sui, C. Wang, J. Kim, J. Wang, S. H. Rhim, and W. Duan, Phys. Rev. B 96, 241105(R) (2017).
[3] Y. J. Kim, M. H. Lee, G. W. Kim, T. Kim, I. H. Cha, Q. A. T. Nguyen, S. H. Rhim, and Y. K. Kim, Acta Mater. 200, 551 (2020).
[4] T. Kim, Q. A. T. Nguyen, G. W. Kim, M. H. Lee, S. I. Yoon, S. H. Rhim, and Y. K. Kim, Appl. Surf. Sci. 609, 155352 (2023).
[5] J. Lee, Q. A. T. Nguyen, D. Kim, J. K. Lee, S. H. Rhim, and Y. K. Kim, Appl. Surf. Sci. 682, 161671 (2025).

Contact

Prof. Dr. Stefan Blügel
Phone: +49 2461 61-4249
Email: s.bluegel@fz-juelich.de

Quynh Anh T Nguyễn
Department of Physics of University of Ulsan in Korea
Email: quynhanh94.dhsp@gmail.com